DIFK (Dependency Injection For Kotlin)

Latest release: 0.1

CI:

Email: [email protected]

License: Apache 2.0

Simple, lightweight and functional IoC framework for Kotlin

• Tired of long XML/JSON gibberish configs?

• Fed up with reflection/byte code magic?

• Want super simple but still functional dependency injection?

Choose DIFK

Example

import DifkInjector
import DifkInjector.addDestructor
import DifkInjector.loadPropertiesFromClasspath
import DifkInjector.addSingleton
import DifkInjector.getProperty
import org.junit.Assert.*
import org.junit.Before
import org.junit.Test

@Test
fun simpleScenario() {
    loadPropertiesFromClasspath("test.properties")
    val dataSource = addSingleton("dataSource", { DataSource(
            getProperty("db.url")!!,
            getProperty("db.driver.class.name")!!,
            getProperty("db.username")!!,
            getProperty("db.password")!!
    ) })
    val dao = addSingleton("dao", { Dao(dataSource) })
    val service = addSingleton("service", { val s = Service(dao); s.init(); s })
    addDestructor { service.close() }
    
    assertFalse(service.closed!!)
    val difkService: Service = getInstance("service")
    assertTrue(service === difkService)
    assertEquals("my_url", difkService.dao.dataSource.url)
    assertEquals("my_class", difkService.dao.dataSource.driverClassName)
    assertEquals("my_user", difkService.dao.dataSource.username)
    assertEquals("my_password", difkService.dao.dataSource.password)
    
    DifkInjector.close()
    assertTrue(service.closed!!)
}

class DataSource(val url: String, val driverClassName: String, val username: String, val password: String)

class Dao(val dataSource: DataSource)

class Service(val dao: Dao) {
    var closed: Boolean? = null

    fun init() {
        closed = false
    }

    fun close() {
        closed = true
    }
}

Features

• 3 types of instances supported: singletons (single instance), prototypes (new instance for every call) and thread locals (new instance for every thread)
• property management support (addPropertiesFromFile, loadPropertiesFromClasspath)
• init and destroy methods support (look at example)
• simple explicit configuration with kotlin code
• preserving your favourite kotlin style
• minimum external dependencies (look at build.gradle)
• no reflection/byte code magic (you're fully in control of your code)
• self-explaining API

Useful tips

• Use registerShutdownHook method to finish your application gracefully (invoke all destroyers) on jvm shutdown